2015-03-31T20:45:19ZThe examination and characterization of a previously unknown mineral from Alcaparrosa, Chilehttp://hdl.handle.net/1974/12176
Title: The examination and characterization of a previously unknown mineral from Alcaparrosa, Chile
Authors: Wakelin, Joshua
Abstract: In the summer of 2013 while working with Jennifer Day, Dr. Ron Peterson encountered a mineral with an unknown X-ray diffraction pattern. This mineral is pale yellow in colour, fibrous, very light, with a texture similar to cotton candy. With examination of the mineral in Dr. Peterson’s accommodations at the research site the XRD signature of the mineral changed from unknown to that of copiapite. Peterson attributed this to the difference in relative humidity between the location of the mineral discovery and his accommodations where the relative humidity was higher. At Queen’s, experiments were conducted with the mineral using the FEI Quanta 650 FEG ESEM and Fourier transform infrared spectroscopy (FT-IR) in the Avatar 320 detector, as well as an attempt to determine the relative humidity at which the mineral is stable. Several methods of sample preparation were attempted using the Avatar 320 including a diamond press, DRIFT, and transmission methods with varying degrees of success. The experiments did show that the mineral does react when it is exposed to an increased relative humidity, in the range of 5 to 22.5%, and results in a shift of the structure of the sulfate group as seen through a shift in the peaks due to sulfur- oxygen bond adsorption detected with the Avatar 320. The FEI Quanta 650 FEG ESEM also showed a significant change in the physical structure of the mineral when exposed to an increased relative humidity that is not observed with the naked eye. The ESEM also allowed for identification of the chemical composition of the mineral whose main components are S, Si, O, and Fe, with smaller amounts of Mg, Al, and K. The mineral also appears to create sulfuric acid when dissolved in fluids as indicated by respiratory distress of those who handled the mineral at the discovery site. This release of sulfuric acid was noted due the mineral’s light and fibrous characteristics that allowed it to become suspended in the air when disturbed and interact with people in the area. The atomic structure and specific chemical composition of this potentially new mineral is still undetermined.2014-05-05T04:00:00ZChironomid assemblage changes and deformity prevalence in lakes impacted by uranium mining in northern Saskatchewan, Canadahttp://hdl.handle.net/1974/12170
Title: Chironomid assemblage changes and deformity prevalence in lakes impacted by uranium mining in northern Saskatchewan, Canada
Authors: Bourne, Vanessa
Abstract: Uranium mining has the potential to have impacts on surrounding ecosystems, particularly on the aquatic organisms found in lakes near mining activities. The objective of this study was to use paleolimnological techniques to investigate whether changes occurred in chironomid assemblages or the deformities in head capsules increased in two lakes (I-7 and I-9) impacted by increases in potentially toxic elements associated with mining activities at the McClean Uranium mine. Elemental concentrations of U, As, Mo and Se (excluding Se in I-9) have significantly increased both lake sediments since the introduction of the mine in the late 1960s. Concentrations of Mo differ between Lake I-7 (400 µg g-1) and Lake I-9 (9 ~25 µg g-1) with both increasing several fold following the mine opening. In Lake I-7, Corynocera ambigua and Zalutchia zaluticola decreased from pre-mining to active-mining conditions while Psectrocladius (monospectrocladius) and Polypedilum nubifer increased. Corynocera ambigua dominated the species assemblage (60%) in the pre-mining time period and reduced to minute amounts during active-mining. In Lake I-9, Corynocera ambigua increased slightly in the post-mining time period but there were only minute changes in other taxa between pre-mining and active-mining time periods. Deformities in chironomid head capsules remained low in both lakes and did not change following the initiation of mining actives. There was insufficient literature pertaining to the ability for Corynocera ambigua, Polypedilum nubifer and Psectrocladius (monospectrocladius) to withstand toxic environments except for Polybedilum nubifer which has been previously recorded to demonstrate resistance to the effects of other metals. The stronger change in chironomid assemblage Lake I-7 could have been observed due to the difference in Mo concentration, geographical placement from mining facility and surface area of lake. Multiple stressors could be impacting chironomid assemblage change, including changes in climate. Temperature data of the area showed a probable increase in average annual air temperature between pre-mining and active- mining time periods. More research is needed to attribute changes in chironomid assemblage changes to increases in elemental concentrations, including the need for reference sites away from mining activities.2014-05-02T04:00:00ZIncreasing Organic Agriculture in Ontario Using Local Food Distribution Systemshttp://hdl.handle.net/1974/12158
Title: Increasing Organic Agriculture in Ontario Using Local Food Distribution Systems
Authors: Buttery, Jessica
Abstract: Various studies have found that organic agricultural methods produce healthier soils with a higher content of organic matter, cause less soil erosion and create less environmental pollution from chemical fertilizers and pesticides. Farms that use organic production methods may also have a greater biodiversity of birds, predatory insects, soil organisms and plants, and emit less greenhouse gases due to lower fossil energy inputs compared to conventional agricultural methods. Studies have also found that purchasing local food reduces the greenhouse gas emissions associated with food transportation, and benefits rural communities and economies. This study seeks to promote organic production methods and local food systems in order to take advantage of the environmental and social benefits of both in order to decrease the negative environmental impact of our food production and distribution systems. The purpose of this study is to determine whether supporting the development of certain types of local food distribution systems can increase the amount of organic agricultural production in Ontario. The main objective of this study is to develop policy recommendations that may be effective in increasing the availability of local, organic food in Ontario and in supporting the development of the local food distribution systems that are used most by organic producers. A high percentage of organic farms use a Community Supported Agriculture (CSA) sales method and 75 percent of CSA farms in Ontario use organic production methods. CSA farms are mainly concentrated in five areas across Ontario. These five areas each have an established customer base, existing infrastructure, and individuals who have knowledge of alternative sales methods and distribution systems. These areas also have a strong network of communication between local producers and the communities that exist in these areas are educated about local food. All of these factors increase the success of a potential local food distribution system. For these reasons, the five areas identified in this study are prime locations for developing local food distribution systems.2014-05-01T04:00:00ZArsenic in Lakes Surrounding Yellowknife: Anthropogenic or Naturally Derived?http://hdl.handle.net/1974/12157
Title: Arsenic in Lakes Surrounding Yellowknife: Anthropogenic or Naturally Derived?
Authors: Howell, Dana
Abstract: One of the oldest and largest mines in the Northwest Territories is Giant Mine, located 5km north of the City of Yellowknife. Over Giant Mine’s 50 years of operation from 1949-1999, it has emitted approximately 20,000 tonnes of arsenic (As) emissions through roasting of arsenopyrite to obtain the submicroscopic amounts of gold. When released into the atmosphere, the As emissions bind with oxygen to form arsenic trioxide (As2O3) which, when dissolved, releases the highly toxic As3+ species into the environment. An additional byproduct of roasting is As-bearing iron (Fe)-oxide. It has been found that high levels of As within the mine property can be attributed to anthropogenic inputs through roasting (Walker et al. 2005, Wrye 2008, Bromstad 2011).
In lake sediments surrounding the Yellowknife region, collected by the Geological Survey of Canada (GSC), high levels of As have been measured. Eleven of these lake sediment samples were made into thin sections and observed through Environmental Scanning Electron Microscopic (ESEM) analysis to determine whether the As present is of natural origin or anthropogenically derived. Further Mineral Liberation Analysis (MLA) was conducted on three of the eleven samples. In all samples studied potential As-bearing phases were observed, including both natural and roaster-derived. The phases observed include arsenopyrite (FeAsS) and pyrite (FeS) of natural origin, As-sulphides and Fe-oxides containing either natural or roaster derived As, and finally As-oxides of roaster origin. MLA analysis on the remaining eight samples, as well as microXRD analysis on the synchrotron is recommended in order to develop more definitive and quantitative conclusions.2014-04-30T04:00:00Z